Patients with more severe depression gain as much clinical benefit from low-intensity interventions, such as self-help books and websites, as those with less severe depression, researchers found.
In a meta-analysis, patients who were more severely depressed at baseline had larger treatment effects with low-intensity interventions than those who were less depressed (coefficient -0.1, 95% CI -0.19 to -0.002), reported Peter Bower, PhD, of the University of Manchester in England, and colleagues online in BMJ.
They cautioned, however, that the magnitude of the interaction was small and may not be clinically significant. Still, it is possible that patients with "more severe depression can be offered low-intensity interventions as part of a stepped-care model."
In the U.K., the standard treatment for depression is a stepped-care approach, in which patients are first treated with low-intensity psychological interventions based on cognitive behavioral therapy (CBT). These typically involve written materials such as self-help books or interactive ones such as videos and websites that require little professional guidance.
High-intensity interventions, such as therapist-led CBT, are usually reserved for those who fail to respond to the low-intensity treatments.
But there's little evidence as to whether the initial severity of depression moderates the effectiveness of low-intensity interventions, the researchers noted, so they conducted a meta-analysis of 16 studies involving 2,470 patients with depression.
The overall effect size of low-intensity interventions was -0.42 (95% CI -0.55 to -0.29), they reported, which translates to a drop of four or five points in depression scores beyond the change seen in controls.
In further analyses, Bower and colleagues found a significant negative interaction between baseline severity and treatment effect, which suggested that patients who are more severely depressed at baseline had larger treatment effects than those who are less severely depressed.
Again, they warned that this drop "would be equivalent to an additional drop of around one point on both [Beck Depression Inventory and Center for Epidemiologic Studies Depression Scale] for a one standard deviation increase in initial severity, an effect which may not be clinically significant."
When the data were analyzed in terms of five severity subgroups, the researchers found a stepwise increase in the effect of low-intensity interventions, from least to most severely ill.
But there were no statistically significant differences in effect sizes across groups, which offers "no indication that patients at the highest levels of severity showed different effects to the overall trend."
The study was limited by the potential for publication bias, reviewer selection bias, and availability bias, but the researchers concluded that their findings suggest using low-intensity interventions could be a first step for all patients, even when the initial severity of depression is high.
"Clearly some patients will not find such interventions useful, and it would seem sensible to continue to refer some cases to more intense psychological intervention or pharmacological management until further evidence is generated confirming our findings," they wrote. "The current data suggest that the threshold could be relatively high if patients are willing to engage in low-intensity interventions."
A co-author reported relationships with GAIA, a company that owns and developed one of the low-intensity interventions involved in the study.
- Reviewed by Zalman S. Agus, MD Emeritus Professor, Perelman School of Medicine at the University of Pennsylvania and Dorothy Caputo, MA, BSN, RN, Nurse Planner